Issues with using arrays C++ - arrays

Question

Sorry to bother you but I have been having issues getting my a motor array to output in this code here.
// initialise motors
// Motor 1
//int in1 = 4;
//int in2 = 2 ;
// Motor 2
//int in3 = 8;
//int in4 = 7;
// Motor 3
//int in5 = 12;
//int in6 = 13;
// Motor 4
//int in7 = 9;
//int in8 = 10;
// Array of PWM's
int thisPin = 0;
uint8_t pwms[] = {3,5,6,11};
byte numberPwms = 4;
// Array for output channels
// Motor 1 (4 = High, 2 = Low)
// Motor 2 (8 = High, 7 = Low)
// Motor 3 (12 = High, 13 = Low)
// Motor 4 (9 = High, 10 = Low)
int mtrpin = 0;
uint8_t motors[] = {4,2,8,7,12,13,9,10};
byte motorPin = 8;
void setup()
{
// pinMode(in1, OUTPUT);
// pinMode(in2, OUTPUT);
// pinMode(in3, OUTPUT);
// pinMode(in4, OUTPUT);
// pinMode(in5, OUTPUT);
// pinMode(in6, OUTPUT);
// pinMode(in7, OUTPUT);
// pinMode(in8, OUTPUT);
for (pwmPin = 0; pwmPin < numberPwms; pwmPin++){
for (mtrPin = 0; mtrpin < motorPin; mtrPin++){
pinMode(motors[mtrPin], OUTPUT);
pinMode(pwms[pwmPin], OUTPUT);
};
};
}
void motorLoop(){
// setting the direction to turn and speed
// digitalWrite(in1, HIGH); // Motor 2
// digitalWrite(in2, LOW);
// digitalWrite(in3, HIGH); // Motor 2
// digitalWrite(in4, LOW);
// digitalWrite(in5, HIGH); // Motor 3
// digitalWrite(in6, LOW);
// digitalWrite(in7, HIGH); // Motor 4
// digitalWrite(in8, LOW);
// Set the speed for the Motors
for(int pwmPin = 0; pwmPin < numberPwms; pwmPin++){
for (mtrPin = 0; mtrpin < motorPin; mtrPin++){
pinMode(motors[mtrPin], LOW);
analogWrite(pwms[pwmPin], 200);
};
};
};
void loop()
{
motorLoop();
delay(500);
}
I have managed to get the initial call to work but I am now turning it all into arrays.
I have managed to get it to work for the PWMs but now after adding the motors array it has stopped working and gives this error message.
In Function 'Void setup()';
41:8: error: 'pwmPin' was not declared in this scope
42:11: error: 'mtrPin' was not declared in this scope
In function 'void motorLoop()';
74:8: error: 'mtrPin' was not declare in this scope.
I know the error will probably be really simple but I can't find to save my life.
Also the for loops have been called as they are now and separate and I am still getting the same errors.
You can see this code at https://www.tinkercad.com/things/fFQKRTjhDrb-motor-initial-turn/editel.
Any help on this would be greatly appreciated :)

Answer 1

In Function 'Void setup()'; 41:8: error: 'pwmPin' was not declared in this scope 42:11: error: 'mtrPin' was not declared in this scope In function 'void motorLoop()'; 74:8: error: 'mtrPin' was not declare in this scope.
As the compiler says: mtrPin has not been declared, and yet, you are using it.
Declarations introduce names in a program, like the name of your variable mtrPin. Other examples are namespaces, functions and classes. A name must be declared before it can be used. You cannot refer to a name which is declared later in the code.
int mtrPin; // this is a (uninitialized) declaration -> mtrPin can be used
int mtrPin { 0 }; // this is a (value) initialization -> mtrPin can be used